1. Field of the Invention
This invention relates to suture packages and more particularly to moisture permeation resistant packages for moisture sensitive suture materials.
2. Description of Prior Art
Heat sealed laminated packages have been used to package sterile sutures for a number of years. The packages are hermetically sealed to provide a perfect barrier against the transmission of bacteria and micro-organisms and preserve the sterility of the suture contained therein indefinitely.
A commonly used package construction is one comprising an outside layer of aluminum foil and an inside layer of a thermoplastic heat sealable material. The aluminum may additionally be covered with a paper or plastic film to reinforce and protect the metal from corrosion and/or to provide a label on the package.
Synthetic absorbable sutures such as homopolymers and copolymers of lactide and glycolide are known to be susceptible to hydrolytic degradation by even minute amounts of water vapor. Great care is accordingly taken during packaging to remove substantially all traces of moisture from the suture and the interior of the package in order to seal the suture in a substantially anhydrous environment. Conventional laminated packages however, while providing a perfect barrier against biological contamination of the suture, have been discovered to provide less than adequate protection against permeation by water vapor. When a conventional package is stored for extended periods of time under condition of ambient temperature and humidity, a significant amount of water vapor is characteristically able to diffuse into the package through the heat seal layer to attack and degrade the moisture sensitive suture material.
It is accordingly an object of the present invention to provide an improved package for moisture sensitive sutures. It is a further object of this invention to provide a metal foil/polymeric film laminate package having great resistance to penetration by water vapor. It is another object of this invention to provide a method whereby the resistance to water vapor permeation of laminate packages constructed of conventional materials may be improved. Yet other objects of this invention will be apparent from the ensuing description and claims.